Pull-socket switch



R. D. SMITH.

FULL SOCKET SWITCH.

APPLICATION FILED OCT 27,1916- RENEWED SEPT-30. 1921.

2 SHEETS-SHEET I.

Patented July 4, 1922.

R. D. SMITH.

PULL SOCKET SWITCH. .APPLICATION FILED OCT. 21, 1916- RENEWEDiSEPTJiU,192l- 1,421,853.

Patented July 4, 1922.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE,

RAYMOND D. SMITH, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO SHAWMUT MACHINEWORKS, INC., .A. CORPORATION OF MAINE.

PULL-SOCKET SWITCH.

Specification of Letters Patent. Patented July 4, 1922. 7

Application filed October 27, 1916, Serial No. 128,132. RenewedSeptember 30,1921. Serial No. 504,494.

To all whom it may concern:

Be it known that I, RAYMOND D. SMITH, a citizen of the United States,residing-at Boston, in the county of Suffolk andCommonwealth ofMassachusetts, have invented certain new and useful Improvements inPull-Socket Switches, of which the following is a specification.

This invention relates to pull sockets with their contained switchmechanisms; and has for its broad object to incorporate in such sockets,and preferably, entirely within the casing-enclosed structure thereof,in compact and durable form, suitable mountings for a plurality of lampsof different candle power arranged preferably so that their individuallighting and extinguishment may be governed by the usual socket pullchain or other switch actuating element.

Through the principles of my invention, the present commercial form ofpull socket caneasily be modified to increase greatly its usefulness byproviding therein such selfcontained means for varying the degree oflight through manipulation of the usual switch controlling pull chain;and this modification may be made at slight increase in cost, orcomplication in construction, and without sacrificing any of thedesirable qualities now developed and existent in this type of socket.vsuch as mechanical ruggedness, ease of assemblage, electricaldurability, and smallness of size.

In the embodiments of my invention herein disclosed, for illustrativepurposes only, I have chosen a pull socket of well known construction,having a circular series of ratchet steps or contact inclines whosebases are disposed in a plane at right angles to the axis of rotation ofthe usual contact bridging plate, and of its oscillatory operatingwheel. Two conductive spring arms of this contact plate are adapted, asusual, to engage simultaneously with diametrically opposite contactinclines. and to leave such inclines abruptly and simultaneously, thusproducing'the quick double break of the circuit recognized as the,bestpractice in this type of switch construction.

I have herein illustrated several novel arrangements by means of whichthis circifically Iemploy, in addition to the usual main lamp, a muchsmaller lamp rigidly mounted upon the socket body and providedwith'circuit connections to the said switch contact inclines, wherebyeach of the said lamps may be put into circuit singly or bothextinguished by successive actuation of the usual switch operating pullchain.

It will be readily appreciated that in the practical use of adouble-lamppull-socket, as proposed above, the lighting of the smaller, or pilot,lamp relative to the usual alternate lighting and extinguishment of themain lamp, would as a rule be for somewhat special and less frequentpurposes, such as for maintaining a night light in the hall or bathroomof a residence. If, however, the lighting of the pilot lamp required anindependent stroke of the socket pull chain, additional to the ordinarysuccessive strokes thereof, for alternately lighting and extinguishingthe main lamp, such additional stroke would be involved in the necessaryactuations for completing each operative cycle of the one-way, movableswitch contact plate; or, in other words, three, rather than the usualtwo, separate, full strokes of the pull chain would be required betweensuccessively lighting or successively extinguishing the main lamp.

To avoid interference with conventional characteristics of socket pullchain control, such as would be occasioned by the condition abovedescribed, I have devised a simple structural arrangement, novel to thetype of switch mechanism concerned, which in one' case permits thesmaller lamp to be switched into circuit by an initial part of that fullstroke of the pull chain which preferably lights the main lamp; thearrangement further being such that a completion of the said full strokewill extinguish the pilot lamp and light the main lamp as usual, andsuch that if said stroke is not completed,

the pilot lamp alone will remain established 100 in circuit. In the:case just described, the alternate full stroke of the pull chain forextinguishing the main lamp remains unconcerned; so that in my improveddoublelamp pull socket, successive full strokes of 105 the pull chainoperate in the usual manner alternately to light and extinguish the mainlamp,-the pilot lamp, in ordinary use becoming only momentarily lightedand then extinguished during the stroke of the pull 110 referred to forproducing differentsequential relationsbetween these or equivalentcurrent-switching effects of successive pull chain strokes.

Various attempts have been made to devise a socket switch structurehaving a single switch adapted to control receptacles for a I pluralityof lamps or other plug attachment devices. But socket switch structureshave reached certain substantially standard forms, and such attemptshave, so-far as I am aware, involved undesirable departure from, andaddition to, the standard, simple, provenly-durable, and commerciallyaccepted socket switch structures. My improvement herein describedprovides aJpIural-receptacle socket switch structure broadly-- and apull socket switch specifically-possessing the desirable features of theapproved forms of structures above referred to, in which substantiallyno departure is made from the standardized arrangement either in generalform, compactness, simplicity of mechanism, or ease of assemblage inmanufacture or installation. For the accomplishment of these objects myinvention resides partially, but not exclusively, in the details ofconstruction, arrangement, and combination hereinafter described andclaimed, and illustrated in the accompanyin drawings.

n the drawings :Fig. 1 is a plan View of my novelly combined socket pullswitch and pilot lamp, the upper insulating cap being shown omitted andthe casing and insulating lining sectioned for clearness; Fig. 2 is asimilar plan view taken in section on the horizontal plane 22 in Fi 3;Fig. 3 is a front view in elevation of t e complete combinedsocketswitch and pilot lamp with casing cut away; Fig. 4 is a rear view inelevation of a portion of the socket structure; Fig. 5 shows'a modifiedarrangement of ratchet inclines and contacts; Fig. 6is a view similar toFig. 5 showing a still different arrangement of ratchet inclines andcontacts; Fig. 7 is a perspective view of the contact-bridging plateused with the construction shown in Figs. 1 to 5, inclusive; Fig. 8 is aperspective view of the actuating wheel used with the plate of Fig. 7Fig. 9 shows a different form of contactrbridging plate adapted for usewith the arrangement of inclines shown in Fig. 6; Fig. 10 illustrates amodified actuating plate for use with the plate of Fig. 9; Figs. v11 to14, inclusive, are diagrammatic and indicate several possiblearrangements of stationary contacts and circuit connections thereto,adapted for embodiment in the structure of Figs. 1 to 5, inclusive;whereby the sequence of lamp control may be varied; Figs. 15 and 16,likewise diagrammatic, indicate different operative arrangements ofcontacts adapted for use with the structure of Fig. 6.

Throughout the different views of the drawings identical parts aredesignated by like numerals.

In Figs. 1 to 4, inclusive, the shell or outer casing appears at 10 andis provided with an insulating lining 11. An upper insulating block 12and a lower insulating block 13 are connected by standards 14, 15 and16. The rotatable contact-bridging plate 17 has two opposite, anddownwardly sloping, spring-arms 18, four equal spaced shoulders 1.9 anda hub 20. The upper surface of the lower insulating block is providedwith four equally spaced inclines denoted as 21, 22, 23 and 24, incircular arrangement, each terminating in an abrupt shoulder. One ofsaid inclines 21 has a contact leaf 25 shaped to conform therewith andto extend therefrom to contact with the base of standard 14 as usual,this standard being insulated from all other metallic parts of thesocket. Another of said inclines 23, diametrically opposite, has a metalleaf 26 conforming with the surface thereof and extending to contactwith a central screw 27 which screw passes upward through the lowerinsulating block and holds clamped to the lower surface thereof thecontact tongue 28 for transmltting current to the main incandescent lamp29.

Above contact plate 17 and concentrically pivoted therewith is the usualinsulating, operating wheel 30, with four equally spaced shoulders3l'adapted, upon full movement thereof in one direction and by ratchetengagement with the shoulders 19, to advance each of the spring arms 18over one of a pair of diametrically opposite'inclines. A spring 33 isprovided to return the wheel 30 when the usual operating chain-34 isreleased into a position for again actuating the contact plate. It willbe noted that the centrally disposed stud 35, which acts as pivot forthe plate 17 and wheel 30 is insulated from all other metallic parts ofthe socket and that in operating to make a circuit the plate 17" actsmerely as an insulated conductor for bridging the contacts 25 and 26.All of the socket switch construction, as thus far described, being wellknown in the art.

On the standard 15 I have shown mounted a miniature threaded shellreceptacle 40. This shell is secured by the insulated screw 41 whichalso holds clamped to the other side of the standard 15, and insulatedtherefrom, a contact leaf 42. The leaf 42 is so extended as to lie uponthe incline 24 in the manner of the contacts 25 and 26. The threadedshell 40 is adapted to receive the base of a small incandescent lamp 43and projects outwardly through the casing, being suitably insulatedtherefrom by a bushing such as 44.

The contact leaf. 25 is extended to occupy also the incline 22 so thatthe contact plate 17 may alwa s have one spring arm in contact with thisleaf, the opposite arm lying either. in contact with the leaf 26 or 42dependent upon the position of the said plate. In Fig. 3it will beapparent that both the large, threaded receptacle 45 for the main lamp,and the small threaded receptacle 40 are permanently in electricalconnection with the standard 15 which standard, in

'turn, is constantly alive with one lead from the supply circuit at thebinding-post screw 47 the other supply lead being attached to thestandard 14 at the binding-post screw 48.

From the above description the operation is obvious, it being plain thatin place of the usual lighting and extinguishment of the main lamp, themain lamp is extinguished and the pilot lamp lighted by one actuation ofthe switch, and' that subsequent actuation lights the main lamp andextin-- guishes the pilot lamp, all parts being selfcontained, durablein construction and as compactly arranged as in the present com- Hmercial form of single lamp socket.

I may, however, vary the number and relation of ratchet inclines andcontacts with or without altering other parts of the switch mechanismand. thereby obtain a greater number of operative effects through thesame actuating agency of single pull element.

For instance, as shown in Fig. 5 I may subdivide each of the two oldquadrant inclines 22 and 24 into two smaller inclines. This arrangementis shown diagrammatically in Figs. 11 and 12 where the inclines 21 and23 with their respective contact leaves 25 and 26 remain unchanged, butwhere two'new incline steps 50 and 51 occupy the quadrant formerlydevoted to the single incline 22 and where the two new incline steps 52and 53 occupy the quadrant formerly devoted to the single incline 24.The arrangement of contacts will be evident from the diagram, it beingnoted that the inclines 50 and 52 are left blank, thus providing for aposition of the contact late 17 in which both main and pilot amps areout of circuit.

Figs. 13 and 14 indicate a similar division of each of the originalinclines 21 and 28 into two separate inclines 55, 56, 57 and 58,respectively, with different arrangements *of circuit connections. Itshould be borne in mind that the contact plate 17 and operating wheel 30(shown detached in Figs. 7 and 8) are provided with four equally spacedratchet-shoulders for producing a rotation of substantially ninetydegrees at each full stroke of the chain, so that arrangements ofinclines and contacts as indicated in Figs.

,alone lighted (by. necessary full actuation).

Pilot lamp alone lighted to main lamp alone lighted (by partialactuation) or back to both lamps out (by full actuation).

Fig. 14.--B0th lamps out to main lamp alone lighted (by necessary fullactuation) main lamp alone lighted to pilot lamp alone lighted (bypartial actuation) or back to both lamps out (by full actuation).

In Figs. 6, 15 and 16, by substituting for the six unevenly dividedinclines of Figs.v 5, and 11 to 14, inclusive, six equally spacedinclines 21, 23, and 60 to 63, inclusive, and by providing acorresponding arrangement of six squally spaced ratchet shoulders 49 onthe plate 17 and corresponding shoulders 59 on the wheel 30 as shown inFigs. 9 and 10, I am able to obtain the same. operative effects ofswitching into circuit each of the lamps singly and of cutting out bothlamps; but here, three complete actuations of the switch are necessaryto complete one operative cycle, Figs. 15 and 16 showing merely adifference in contact arrangement for varying the sequence of operation.

Although all of the above-described modi- F fications for varying thesequential relation of lamp lighting and extinguishment contemplatespecifically the connection of each lamp singly to the supply circuit,it will be obvious to those skilled in the art that such modificationswould be available in systems of electrical connection where both lamps,for one position of the switch, are connected to the supply circuit inseries relationsuch systems "of connection, however, being merely amatter of choice and well known in the art pertaining to plural lampsocket switches.

It is immaterial to the spirit of my invention what type of socketstructure is employed, either as to its precise switch mechanism oroutward form and provision therein for mechanical and electricalconnection to the means of support. Those skilled in the art willappreciate that my invention may be as readily embodied in that type ofsocket-switch commonly known as an adapter, as in the herein illustratedpermanent or fixture form of socket.

Without, therefore, limiting the scope of my invention to the preciseform and mechanical arrangement of pull socket-switch herein describedand illustrated, what I claim as new is I 1. In a pull-socket having abody structure comprising a top insulating block and a bottom insulatingblock secured together in spaced relation, in combination; a doublebreak pull switch embodying a two-armed t electrical connection to oneof a different pair of said contacts and opening outwardly at the sideof said structure.

2. In a pull-socket having a body structure comprising a top insulatingblock and a bottom insulating block secured together in spaced relation,in combination; adoublebreak pull switch embodying a two-armedratchet-driven current distributor pivotally mounted to rotate:between'said blocks, said switch including three or more stationarycontacts mounted in circular arrangement on the upper surface of. thebottom block and so spaced that predetermined pairs of said contacts maybe conductively bridged by said distributor; a main lamp receptacledepending from the lowersurface of said bottom insulating block andhaving electrical connections to one of said pairs of contacts; and anauxiliary plug receptacle mounted on the pull socket body structureadjacent the said distributor, said auxiliary receptacle havingelectrical connection to one of a diflerent pair of said contacts andopening outwardly at the side of said structure.

3. In a pull-socket having a body structure comprising a top insulatingblock and a bottom insulating block secured together in spaced relation,in combination; a doublebreak pull switch embodying a two-armedratchet-driven current distributor pivotally mounted to rotate betweensaid blocks, said switch including three or more stationary contactsmounted in circular arrangement on one of said blocks and so spaced thatpredetermined pairs of said contacts may be conductively bridged by saiddistributor; a main lamp receptacle depending from the lower surface ofsaid bottom insulating block and having electrical connections to one ofsaid pairs of contacts; and an auxiliary plug receptacle mounted on thepull socket body structure between the said two insulating blocks andperipherally adjacent the said distributor, said auxiliary receptaclehaving electrical connection to one of a different pair of said contactsand opening outwardly at the side of said structure.

4. In a pull-socket having a body structure including circular top andbottom insulating blocks secured together in spaced relation with rigidconductive members extending between said insulating blocks at theperipheral edges thereof, in combination; pull switch mechanism mountedto operate in the space between said insulating block and between saidrigid conductive members, including stationary con tacts mounted on oneof said blocks; a main lamp receptacle depending from the lower surfaceof said bottom insulating block; and an auxiliary plug receptaclemounted rigidly on one of said conductive members between saidinsulating blocks and laterally of the pull switch mechanism, each ofsaid receptacles bein electrically connected to respectively di erentones of said stationary contacts thereby to be electrically governedthrough the said switch mechanism.

5. In a pull-socket having supply circuit terminals and including a bodystructure comprising top and bottom insulating blocks secured in spacedrelation by conductive brackets extending therebetween, the combinationwith said structure, of a pawl-and-ratchet-actuated switch mechanismmounted between said blocks and including an oscillatory driving devicewith means to limit its stroke to a' partial rotation and resilientmeans tending to restore it to a definite position at one end of thedesigned stroke; a rotatable conductive, double-ended current-switchingmember pivoted to be rotated by said device; a plurality of circuitcontacts arranged to be successively engaged by said member indiametrically opposite pairs, with insulating supports for said contactsarranged cooperatively with said member to restrict retrogressivemovement thereof between successive contacts; a main two-terminal lampreceptacle depending from the lower surface of said bottom insulatingblock; an auxiliary two-terminal plug receptacle carried by said bodystructure;

insulated ,fixed circuit connections between one, terminal of each ofsaid receptacles and a common supply circuit terminal; and separatecircuit connections between the other terminal of each of saidreceptacles and members of different pairs of said stationary contacts;together with insulated fixed circuit connection between the relatedmembers of said lastmentioned pairs and another supply circuit terminal;-more than one of the said pairs of contacts being successivelydisposed within the travel of said member caused by a full stroke ofsaid device, whereby different connection of said receptacles to thesupply circuit may be had through a full or partial strokerespectivelyof said device.

6. In a pull-socket having a body structure comprising a top and abottom insulating block secured together in spaced relation, incombination double-break! current switching mechanism mounted to operatebetween said blocks and embodying an oscillatory actuator with means tolimit its stroke and resilient means tending to restore it to thebeginning of its stroke; a two-armed current-switching member arrangedto be r0tatively advanced by successive strokes'of said actuator, andthree or more stationary contacts fixedly mounted on insulating stepformations and circularly arranged to be conductively bridged by saidmember in diametrically opposite pairs; a main lamp receptacle dependingfrom the lower surface of the bottom insulating block; and an auxiliaryplug receptacle carried laterally of the pull-socket body structure;-each of said receptacles being electrically connected to one ofrespectively different pairs of contacts thereby to be electricallyenergized in respectively different positions of said current-switchingmember.

7. In a pull-socket including a body structure comprising top and bottominsulating blocks secured in spaced relation by con-' ductive bracketsextending therebetween, the combination with said structure of a pawlandratchet actuated, current supplied, switch mechanism mounted betweensaid blocks and embodying an oscillatory driving device with means tolimit its stroke and resilient means tending to restore it to a definiteposition at one end of the designed stroke; a rotatablecurrent-switching memher arranged to be rotated by said device; aplurality of circuit contacts with insulating support formationsarranged to be successively engaged by said member in its rotativemovement and arranged co-operatively therewith to restrict retrogressivemovement thereof; a main lamp receptacle depending from the lowersurface of said bottom insulating block; an auxiliary lamp receptaclecarried by said body structure between said top and bottom insulatingblocks, and disposed laterally thereof; and independent electricalconnections between each of said two lamp receptacles and a separate'one of said contacts ;more than-one of the said contacts being disposedwithin the full stroke limit of said device and member driven thereby,whereby selective circuit control through said member may be had by afull or partial stroke of said device.

8. In a pull-socket including a body structure comprising top' andbottom insulating blocks secured in spaced relation by 'conductivebrackets extending therebetween; the combination with said structure ofa pawland ratchet actuated, current supplied, switch mechanism mountedbetween said blocks and embodying an oscillatory driving device withmeans to limit its stroke to a partial rotation and resilient meanstending to restore it to a definite position at one end of the designedstroke; a rotatable currentswitching member arranged to be rotated bysaid device; a plurality of circuit contacts with insulating supportformations arranged to be successively engaged by said member in itsrotative movement andarranged co-op-- erat-ively therewith to restrictretrogressive movement thereof; a main lamp receptacle depending fromthe lower surface of said bottom insulating block; an auxiliary lampreceptacle rigidly mounted on one ofsaid brackets substantially betweensaid two insulating blocks and disposed to extend outwardly andlaterally thereof; and independent electrical connections between eachof said two lampreceptacles and a separate one of said contacts ;-morethan one of. the said contacts being disposed within the full strokelimit of said device and member driven thereby, whereby selectivecircuit control through said member may be had by a full or partialstroke of said device.

9. A pull socket switch having two plpg receptacles controlled by asingle switch and embodying two parallel-positioned, substantiallycircular, insulating plates held in spaced concentric relation; tworigid conductive brackets extending between said plates and adjacent theperipheries thereof; a switch concentrically mounted on and between saidplates and having a concentrically-pivoted, pull-actuatable rotativetwo-- armed wiper, and also a plurality of co-operative pairs ofdiametrically opposite, stationary contacts mounted on one of saidplates and circularly arranged so that the co-operative pairs thereofare conductively bridged in different rotative positions of the wiper;a, two-pole rim-and-centre-contact plug receptacle concentricallymounted on the outer face of one of said plates; and a second andsimilar two-pole plug receptacle mounted laterally of the switch on oneof said brackets ;-the two poles of each of said receptacles havingfixed electrical connection to different stationary contacts and to saidlast mentioned bracket, respectively;- together with fixed electricalconnection from the other of said brackets to the cooperative stationarycontacts that are diametrically opposite the said different stationarycontacts.

10. A pull socket switch having two plug receptacles controlled by asingle switch and embodying two parallel-positioned, substantiallycircular, insulating plates held in spaced concentric relation; tworigid conductive brackets extending between said plates and adjacent theperiphery thereof a switch concentrically mounted on and between saidplates and having a double-ended, concentrically-pivoted,pull-actuatable rotating, conductive wiper, and also a plurality ofco-operative pairs of diametrically opposite, stationary contactsmounted on one of said plates and circularly arranged, to be bridged bythe wiper;--a plug receptacle concentrically mounted on the outer faceof said plates ;-a fixed connection from the center contact of said plugreceptacle extending from beneath the switch pivot to one of a pair ofsaid stationary contacts ;-a second plug receptacle mounted laterally ofthe switch and conductively on one of said brackets;a bracketinsulated,center holding screw and contact for said, last mentioned receptacle,conductively connected to one of another pair of said stationarycontacts;fixed' conductive connection from said bracket to the otherreceptacle ;and fixed conductive connections from the other bracket tothe opposite members of each of said last mentioned two pairs ofstationary contacts.

11. A current-supplied pull socket switch mechanism for governing pluralcircuits embodying, in combination, an oscillatory switch-operatingdevice with means to limit its rotative stroke and resilient meanstending to restore it to a normal position at one end of its limitedstroke; a rotatable current-distributing member arranged to beintermittently advanced through pawl-andratchet driving engagementtherewith by said device; a plurality of fixed contacts connected inrespectively different load circuits and arranged to be engagedsuccessively by said member for energizing the loads; and detent meansarranged to prevent retrogressive movement of said member betweencontacts more than one of the said contacts being disposed within thepath of travel of said member as caused by the said limited stroke ofsaid device, whereby a full stroke and a partial stroke of said deviceoperate respectively to establish said member in engagement withdifferent ones of said fixed contacts, thereby to energize respectivelydifferent load circuits.

12. A current-supplied pull socket switch mechanism for governing pluralcircuits embodying, in combination, an oscillatory switch-operatingdevice with means to limit its rotative stroke and resilient meanstending to restore it to normal position at one end of its limitedstroke; a rotatable currentdistributing member arranged to beintermittently advanced through pawl-andratchet driving engagementtherewith by said device; a plurality of fixed contacts connected inrespectively different load circuits and arranged to be engagedsuccessively by said member for energizing the loads; and insulatingformations supporting said contacts and formed co-operatively With saidmember as incline steps with abrupt shoulders for normally positioningthe latter and for preventing retrogressive movement of said memberbetween contacts; more than one of the said insulating formations withits supported contact being disposed within the path of travel of saidmember as caused by the said limited stroke of said device, whereby afull stroke and a partial stroke of' said device operate respectively toestablish said member in engagement with different ones of said fixedcontacts, thereby to energize respectively different load circuits.

13. In a pull socket switch structure, in combination, an oscillatoryoperating device with means to limit its rotative stroke and resilientmeans tending to restore it to a normal position at one end of itslimited stroke a rotatable current-switching member arranged to beintermittently advanced by successive forward strokes of said devicethrough paWLand-ratchet driving engagement therebetween; and a pluralityof fixedly mounted contacts positioned to be successively engaged bysaid member in its rotative advance; means to prevent retrogressivemovement of said member between contacts; and a plurality ofcurrent-translative electric load units mounted on the socket structureand electrically connected respectively to different ones of saidcontacts; more than one of the said contacts being disposed within thepath of travel of said member as caused by the said limited stroke ofsaid device, whereby different circuits through said units may beoperated respectively by a full stroke and by a partial stroke of saiddevice.

14. In a pull socket switch structure, in combination, an oscillatoryoperating device with means to limit its rotative stroke and resilientmeans tending to restore it to a normal position at one end of itslimited stroke; a rotatable current-switching member arranged to beintermittently advanced by successive forward strokes of said devicethrough pawl-and-ratchet driving engagement therebetween; and aplurality of fixedly mounted contacts positioned to be successivelyengaged by said member in its rotative advance; insulating formationssupporting said contacts and formed cooperatively with said member asdetent steps for normally positioning the same and for preventingretrogressive movement of said member between contacts; and a pluralityof current-translative electric load units mounted on the socketstructure and electrically connected respectively to different ones ofsaid contacts ;more than one of the said contacts being disposed withinthe path of travel of said member as caused by the said limited strokeof said device, whereby diiferent circuits through said units may beoperated respectively by a full stroke and by a partial stroke of saiddevice.

15. In a pull socket switch, the combination with an insulating blockhaving incline formations, and leaf contacts carried on the inclinesurface of selected formations for governing different circuits throughthe switch; of a rotatable contact plate having downwardly extendingconductive arms which are adapted to engage either the inclineformations or the said leaf contacts carried thereon, in diametricallyopposite pairs; a pull-actuatable operating plate mounted to oscillateand adapted to engage with said contact plate for positively impellingthe same intermittently in a constant rotative direction, thereby toadvance said plate arms successively'over said incline formations; and aspring acting to retainthe said contact plate and said operating platein operative position and to return the operating plate to its normalposition after each forward stroke thereof; together with stop meansarranged to limit the full stroke of said operating plate to such pathand extent of rotative travel relative to the position and spacingrespectively of said incline formations, that said full stroke isoperative to ad- Vance said contact plate arms over a plurality butlimited number of consecutive incline formations, whereby a full and apartial pull-actuation of said operating plate may position said armsfor engagement with respectively different pairs of inclineforformations, and leaf contacts carried on the incline surface ofselected formations for governing different circuits through the switch;of a rotatable contact plate having downwardly extending conductive armswhich are adapted to engage either the incline formations, or the saidleaf contacts carried thereon, in diametrically opposite pairs; apull-actuatable operating plate mounted to oscillate and adapted toengage with said contact plate for positively impelling the sameintermittently in a contact rotative direction, thereby to advance saidplate arms successively over said incline formations; and a springacting to retain the said contact .plate and said operating plate inoperative position and to return the operating plate to its normalposition after each forward stroke thereof; one'of the said leafcontacts being formed and extended to occupy a plurality of the saidincline formations whereby said extended leaf contact may be connectedelectrically with different ones of' the other leaf contacts inrespectively different rotative positions of said contact plate. Signedat Boston, Massachusetts, this 26th day of October, 1916.

RAYMOND D. SMITH.

, Witnesses:

JAMES D. GORDON, E. LILLIAN MOFADDEN.

